Modoc (AMNH 604)

Modoc (AMNH 604)

Exhibition Text

Wrapped in black glass

Rocks floating through the vacuum of space are chilled to well below freezing. When a meteorite passes through Earth's atmosphere, its inside stays cold even as its surface melts away. Before it hits the ground, the molten surface solidifies into a thin glassy coating, called fusion crust. Crystals of magnetite—an iron-oxide mineral—color the fusion crust black. The broken surface of Modoc shows contrast between its lighter-colored interior and its dark fusion crust.